Sodium metabisulfite is a white or slightly yellow crystalline powder with a strong SO2 odor. Sodium metabisulfite has stronger reducing properties than sulfites and acts similarly to sodium sulfite.

The use of sodium metabisulfite in processed food should pay attention to the following points:
1)Sodium metabisulfite is a reducing bleaching agent, and its solution is unstable and volatile, so it should be used now in order to prevent sulfite from being unstable and volatile.

2) The presence of metal ions in the food, the residual sulfite can be oxidized; also can make the reduced pigment oxidation discoloration, thus reducing the effectiveness of bleach. So use metal chelating agent at the same time in production.

3)Substances bleached with sulfites, due to the disappearance of sulfur dioxide and easy to recolor, so usually in the food residual excess sulfur dioxide, but the residual amount shall not exceed the standard.

4) Sulfite can not inhibit the activity of pectinase, will be detrimental to the cohesion of pectin. In addition sulfite infiltrated into the fruit tissue, the processing of broken fruit, in order to get rid of sulfur dioxide, so the fruit preserved with sulfite is only suitable for the production of jams, dried fruits, fruit wines, preserves, etc., can not be used as raw materials for canning.

5) Sulfite can destroy thiamine, so it is not easy to use for fish food.

6) Sulfites are easy to react with aldehydes, ketones, proteins and so on.

Storage Precautions:

Store in a cool, dry and well ventilated warehouse. Keep away from fire and heat source. Keep the container sealed. It should be stored separately from oxidizers, acids and edible chemicals, and should not be mixed. It should not be stored for a long time to avoid deterioration. The storage area should be equipped with suitable materials to shelter spills.

Storage and expiration date:

Shield from light and keep sealed.

Application of sodium metabisulfite in food:
At present, in the processing and preservation of light-colored vegetables in China, such as mushrooms, lotus root, horseshoes, white asparagus, yam and other products. More than the use of sodium metabisulfite solution for color protection, of course, there are some differences in the process of each plant, such as in the canned mushrooms in the processing of fresh mushrooms in a timely manner with an aqueous solution containing sodium metabisulfite 0.03g/kg soaked 2 times, each time 1-2min.

In the cookie industry, sodium metabisulfite is used as a cookie dough improver, which is prepared into a 20% solution before use, and added into the immature dough in batches during the dough modulation process.

As the sulfur dioxide released by sodium metabisulfite in the process of dough modification has an abating effect on the gluten strength of the dough, when the gluten strength and toughness of the flour is large, a small amount is added to prevent deformation of the finished cookie product due to excessive gluten strength. Toughness of the dough can be added according to the flour gluten strength discretion, and generally in the high proportion of oil and sugar in the shortening dough as far as possible not to use, this is because the addition of oil and sugar itself has prevented the expansion of gluten protein absorption, preventing a large number of gluten formation, without the need to add sodium metabisulfite.